Preeclampsia remains a significant cause of maternal mortality, underscoring the importance of understanding its pathophysiology. Noninvasive monitoring, which can be conducted by analyzing breathing rate fluctuations, specifically examining their asymmetrical patterns, is an area of interest in studying physiological signal complexity. This study compares asymmetrical features in breath-to-breath time series between women with severe preeclampsia and normotensive women. Our study involved the analysis of a dataset containing short-term, continuous respirogram recordings of women in labor, which included those diagnosed with severe preeclampsia (22 women) and a normotensive control group (35 women). From these recordings, we derived the breath-to-breath (BB) time series and computed asymmetrical features such as Porta’s index (P%), Guzik’s index (G%), and Ehlers’s index (E), as well as measures of asymmetrical entropy including the entropy of acceleration runs (HAR), entropy of deceleration runs (HDR), and total entropy (H). For comparison, the mean respiratory or breathing rate was calculated for both groups. We found that the HDR, G%, and E showed significant differences between C and SP associated with preeclampsia; HDR: 1.00 ± 0.08 vs. 1.06 ± 0.10, p = 0.02; G%: 49.3 ± 2.5% vs. 47.6 ± 2.3%, p = 0.007 and E: -0.48 ± 1.20 vs. -1.25 ± 1.32, p = 0.0136, respectively. Our study suggests that breathing rate decelerations are lower in parturient women with severe preeclampsia compared to normotensive counterparts, as indicated by lower G%. Furthermore, women with preeclampsia exhibited a more asymmetric pattern of respiratory frequency fluctuations and a higher HDR value than their normotensive counterparts.